From 2f3669b767129bc8739bb03e80abc65eb54a3471 Mon Sep 17 00:00:00 2001
From: Winson <chiuwinson@google.com>
Date: Fri, 11 Jan 2019 11:28:34 -0800
Subject: Add function to return path for last resolved resource

After an AssetManager.FindEntry call is made, either directly or from any of the resource entry calls, a stack of the steps taken to resolve the resource is saved. Those steps can be retrieved as a log later on by calling AssetManager.GetLastResourceResolution, which returns a formatted string of the resource ID/name and path taken, including the configs and package names of each step.

Logging and the saving of the steps to memory can be enabled/disabled with the @hide .setResourceResolutionLoggingEnabled() method on AssetManager.

Bug: 122374289

Test: cases for single and multi ApkAssets loaded
Test: case for no resolution made
Test: made test app to display log on device
Test: added debugging call to source and ran through on-device apps

Change-Id: I6a32b8d4020c3f8510032ff7f431510089fff43f
---
 libs/androidfw/include/androidfw/AssetManager2.h | 50 ++++++++++++++++++++++++
 libs/androidfw/include/androidfw/ResourceUtils.h | 12 ++++++
 2 files changed, 62 insertions(+)

(limited to 'libs/androidfw/include')

diff --git a/libs/androidfw/include/androidfw/AssetManager2.h b/libs/androidfw/include/androidfw/AssetManager2.h
index 0d492984d41d..f29769b834d1 100644
--- a/libs/androidfw/include/androidfw/AssetManager2.h
+++ b/libs/androidfw/include/androidfw/AssetManager2.h
@@ -229,6 +229,14 @@ class AssetManager2 {
                                    ResTable_config* in_out_selected_config, uint32_t* in_out_flags,
                                    uint32_t* out_last_reference) const;
 
+  // Enables or disables resource resolution logging. Clears stored steps when
+  // disabled.
+  void SetResourceResolutionLoggingEnabled(bool enabled);
+
+  // Returns formatted log of last resource resolution path, or empty if no
+  // resource has been resolved yet.
+  std::string GetLastResourceResolution() const;
+
   // Retrieves the best matching bag/map resource with ID `resid`.
   // This method will resolve all parent references for this bag and merge keys with the child.
   // To iterate over the keys, use the following idiom:
@@ -346,6 +354,48 @@ class AssetManager2 {
   // Cached set of bags. These are cached because they can inherit keys from parent bags,
   // which involves some calculation.
   std::unordered_map<uint32_t, util::unique_cptr<ResolvedBag>> cached_bags_;
+
+  // Whether or not to save resource resolution steps
+  bool resource_resolution_logging_enabled_ = false;
+
+  struct Resolution {
+
+    struct Step {
+
+      enum class Type {
+        INITIAL,
+        BETTER_MATCH,
+        OVERLAID
+      };
+
+      // Marks what kind of override this step was.
+      Type type;
+
+      // Built name of configuration for this step.
+      String8 config_name;
+
+      // Marks the package name of the better resource found in this step.
+      const std::string* package_name;
+    };
+
+    // Last resolved resource ID.
+    uint32_t resid;
+
+    // Last resolved resource result cookie.
+    ApkAssetsCookie cookie = kInvalidCookie;
+
+    // Last resolved resource type.
+    StringPoolRef type_string_ref;
+
+    // Last resolved resource entry.
+    StringPoolRef entry_string_ref;
+
+    // Steps taken to resolve last resource.
+    std::vector<Step> steps;
+  };
+
+  // Record of the last resolved resource's resolution path.
+  mutable Resolution last_resolution;
 };
 
 class Theme {
diff --git a/libs/androidfw/include/androidfw/ResourceUtils.h b/libs/androidfw/include/androidfw/ResourceUtils.h
index d94779bf5225..eb6eb8e66175 100644
--- a/libs/androidfw/include/androidfw/ResourceUtils.h
+++ b/libs/androidfw/include/androidfw/ResourceUtils.h
@@ -17,6 +17,7 @@
 #ifndef ANDROIDFW_RESOURCEUTILS_H
 #define ANDROIDFW_RESOURCEUTILS_H
 
+#include "androidfw/AssetManager2.h"
 #include "androidfw/StringPiece.h"
 
 namespace android {
@@ -27,6 +28,17 @@ namespace android {
 bool ExtractResourceName(const StringPiece& str, StringPiece* out_package, StringPiece* out_type,
                          StringPiece* out_entry);
 
+// Convert a type_string_ref, entry_string_ref, and package
+// to AssetManager2::ResourceName. Useful for getting
+// resource name without re-running AssetManager2::FindEntry searches.
+bool ToResourceName(StringPoolRef& type_string_ref,
+                    StringPoolRef& entry_string_ref,
+                    const LoadedPackage* package,
+                    AssetManager2::ResourceName* out_name);
+
+// Formats a ResourceName to "package:type/entry_name".
+std::string ToFormattedResourceString(AssetManager2::ResourceName* resource_name);
+
 inline uint32_t fix_package_id(uint32_t resid, uint8_t package_id) {
   return (resid & 0x00ffffffu) | (static_cast<uint32_t>(package_id) << 24);
 }
-- 
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